The binding of serum IgM antibodies, including M-proteins, to glycolipids or glycoproteins is associated with several chronic polyneuropathy syndromes (O'Leary, C. P. and Willison, J. J., Curr. Opin. Neurol. 13:583–588 (2000); Quarles, R. H. and Weiss, M. D., Muscle Nerve 22:800–822 (1999)). IgM binding to myclin-associated glycoprotein (MAG) is a marker for a demyelinating sensory-motor polyneuropathy syndrome (Nobile-Orazio, “Neuropathies associated with anti-MAG antibodies and IgM monoclonal gammopathies,” in Latov, N., Wokke, J. H. J., Kell, J. J. Jr., Eds., Immunology and Infectious Diseases of the Peripheral Nerves, Cambridge, UK: Cambridge University Press, 1998:168–189; Erb, S. et al., J. Neurol. 247:767–772 (2000)). IgM binding to sulfatide (Lopate, G., et al., J. Neurol. Neurosurg. Psychiatry 62:581–585 (1997); Carpo, M. et al., J. Neurol. Sci. 176:144–150 (2000); Erb, S. et al., J. Neurol. 247:767–772 (2000)) and to β-tubulin (Connoly, A. M. et al., Neurology 48:243–248 (1997)) may also be associated with demyelinating sensory-motor polyneuropathies. IgM binding to GM1 ganglioside is related to a multifocal motor neuropathy that commonly has conduction block as the predominant demyelinating feature on electrophysiological testing (Parry, G., Muscle Nerve 19:269–276 (1996); Pestronk, A. and Choksi, R., Neurology 49:1289–1292 (1997); Pestronk, A., Neurology 51:S22–S24 (1998)). Serum IgM with selective binding to GD1b ganglioside is associated with an axonal sensory polyneuropathy and ophthalmoplegia (O'Leary, C. P. and Willison, J. J., Curr. Opin. Neurol. 13:583–588 (2000); Susuki, K. et al., J. Neuroimmunol. 112:181–187 (2001)). However, the antigenic targets of serum antibodies in approximately 40% of patients with IgM M-proteins and polyneuropathies, especially those with primary axonal involvement, have been undefined.
Because polyneuropathies are potentially treatable, correct identification of a patient's particular polyneuropathies is important. Methods of diagnosing such polyneuropathies based on specific disease-related criteria would facilitate identification of treatable disease and expedite commencement of treatment.